1. Technical Field
2. Related Applications
3. Background Art
The following copending patent application is related to this invention and is incorporated herein by reference: B. Brachtl, et al., "Controlled Use of Cryptographic Keys via Generating Stations Established Control Values", Ser. No. 55,502, filed March 1987, and assigned to IBM Corporation.
The cryptographic transformation of data is ordinarily defined by a selected algorithm, or procedure, under the control of a key. Since the algorithm is normally public knowledge, protection of the transformed, or enciphered, data depends on secrecy of the key. Thus the key must be kept secret to prevent an opponent from simply using the known algorithm and key to recover the enciphered data. The protection of the data therefore hinges on the protection of secret keys.
Key Management encompasses the facilities, functions and procedures in a cryptographic system to handle cryptographic keys and key-related information in such a way as to protect the secrecy and integrity of the keys.
In order to support the primary cryptographic requirements of a user or host system, the system Key Management facility usually supports several capabilities including, Key Installation, Key Storage, Key Generation, and Key Distribution for both importing and exporting keys.
In all cases the general objective is to prevent unauthorized disclosure or modification of cryptographic keys.
Since enciphered data may be exchanged by systems employing the same cryptographic algorithm, the ability to exchange a secret key or keys may be necessary. In order to protect the privacy of a secret key during its shipment from the key originator to the intended recipient, the key itself must be enciphered under another secret key (already shared by the two parties). Key distribution protocols must be defined to support compatible, secure exchange of keys among cryptographic systems.
The storage of keys on insecure media (i.e., storage not within a secure area) requires that keys themselves be enciphered. The Master Key concept is one in which all keys used by a cryptographic system are stored in enciphered form under a single key called the Master Key. The Master Key itself must be protected from disclosure or modification. Non-cryptographic means are usually provided to protect the Master Key (such as physical access control).
The prior art has failed to provide a practical and flexible Key Management system which maintains high data security standards.